bluetooth_people_counting_ak9753

Bluetooth - People Counting (AK9753)

Overview

This project aims to implement a people counting application using SparkFun Human Presence Sensor Breakout - AK9753 (Qwiic) and Sparkfun development board Sparkfun Thing Plus MGM240P with integrated BLE stack.

Gecko SDK Suite version

• GSDK v4.4.0
• Third Party Hardware Drivers v2.0.0.0

Hardware Required

• SparkFun Thing Plus Matter - MGM240P - BRD2704A
• SparkFun Human Presence Sensor Breakout - AK9753 (Qwiic)
• SparkFun Micro OLED Breakout (Qwiic)

NOTE: Tested boards for working with this example:

Board ID	Description
BRD2704A	SparkFun Thing Plus Matter - MGM240P - BRD2704A
BRD2601B	EFR32xG24 Dev Kit - xG24-DK2601B
BRD2703A	EFR32xG24 Explorer Kit - XG24-EK2703A
BRD4108A	BG22 Bluetooth SoC Explorer Kit - BG22-EK4108A
BRD4314A	BGM220 Bluetooth Module Explorer Kit - BGM220-EK4314A

Connections Required

The hardware connection is shown in the image below: Listed below are the port and pin mappings for working with this example.

• Board: BRD2704A - SparkFun Thing Plus Matter - MGM240P

  GPIO Pin	Connection	Pin function
  GPIOB	PB00	Button
  SCL	PB03	I2C Clock
  SDA	PB04	I2C Data

• Board: BRD2601B - EFR32xG24 Dev Kit- xG24

  GPIO Pin	Connection	Pin function
  GPIOB	PB02	Button
  SCL	PC04	I2C Clock
  SDA	PC05	I2C Data

• Board: BRD2703A - EFR32xG24 Explorer Kit - XG24

  GPIO Pin	Connection	Pin function
  GPIOB	PB02	Button
  SCL	PC04	I2C Clock
  SDA	PC05	I2C Data

• Board: BRD4108A - BG22 Bluetooth SoC Explorer Kit - BG22

  GPIO Pin	Connection	Pin function
  GPIOB	PC07	Button
  SCL	PD02	I2C Clock
  SDA	PD03	I2C Data

• Board: BRD4314 Bluetooth Module Explorer Kit

  GPIO Pin	Connection	Pin function
  GPIOB	PB00	Button
  SCL	PD02	I2C Clock
  SDA	PD03	I2C Data

Setup

To test this application, you can either create a project based on an example project or start with a "Bluetooth - SoC Empty" project based on your hardware.

NOTE:

• Make sure that the SDK extension is already installed and this repository is added to Preferences > Simplicity Studio > External Repos.

• SDK Extension must be enabled for the project to install the required components.

Create a project based on an example project

1. From the Launcher Home, add your hardware to MyProducts, click on it, and click on the EXAMPLE PROJECTS & DEMOS tab. Find the example project with the filter "people".

2. Click Create button on the Bluetooth - People Counting (AK9753) example. Example project creation dialog pops up -> click Create and Finish and Project should be generated.

3. Build and flash this example to the board.

Start with a "Bluetooth - SoC Empty" project

1. Create a Bluetooth - SoC Empty project for your hardware using Simplicity Studio 5.

2. Copy all attached files in inc and src folders into the project root folder (overwriting existing app.c).

3. Import the GATT configuration:

   • Open the .slcp file in the project.

   • Select the CONFIGURATION TOOLS tab and open the Bluetooth GATT Configurator.

   • Find the Import button and import the attached gatt_configuration.btconf file.

   • Save the GATT configuration (ctrl-s).

4. Open the .slcp file. Select the SOFTWARE COMPONENTS tab and install the software components:

   • Install [Platform] > [Driver] > [I2CSPM] component with the default instance name: qwiic.
   • Install [Platform] > [IO Stream] > [IO Stream: USART] component with the default instance name: vcom.
   • Install [Platform] > [Driver] > [Button] > [Simple Button] component with the instance name: btn0.
   • Install [Bluetooth] > [NVM] > [NVM Support] component.
   • Install [Application] > [Utility] > [Log] component.
   • [Third Party Hardware Drivers] → [Display & LED] → [SSD1306 - Micro OLED Breakout (Sparkfun) - I2C] → use default configuaration
   • [Third Party Hardware Drivers] → [Service] → [GLIB - OLED Graphics Library]
   • [Third Party Hardware Drivers] → [Sensors] → [AK9753 - Human Presence Sensor (Sparkfun) - I2C]

5. Build and flash the project to your device.

NOTE:

• Some boards do not have an integrated button. In this case, the user has to connect an external button to the board and config this button in accordance with project specifics. To make the driver more stable, use a ceramic capacitor (ex: Ceramic Capacitor 104) to avoid the anti-vibration button used in the project as below:

• Do not forget to flash a bootloader to your board, see Bootloader for more information.

How it Works

Application overview

GATT Configuration

The application is based on the Bluetooth - SoC Empty example. Since the example already has the Bluetooth GATT server, advertising, and connection mechanisms, only minor changes are required.

A new custom service (People Counting) with 8 characteristic must be added.

• People Entered So Far:

  • [Readable] - Get total number of people enter the room

  • [Writable] - Clear total number of people enter the room

• People Count:

  • [Readable] - Get number of people in the room

  • [Writable] - Clear number of people in the room

• Room Capacity:

  • [Readable] - Get the capacity of the room

  • [Writable] - Set the capacity of the

  • [Notifiable] - Get notification of room status( full or empty)

• Lower Threshold:

  • [Readable] - Get the lower threshold

  • [Writable] - Set the lower threshold

• Upper Threshold:

  • [Readable] - Get the upper threshold

  • [Writable] - Set the upper

• IR Threshold:

  • [Readable] - Get the IR threshold

  • [Writable] - Set the IR threshold

• Hysteresis:

  • [Readable] - Get hysteresis

  • [Writable] - Set hysteresis

• Notification status:

  • [Readable] - Get the notification status

  • [Writable] - Set the notification status

People Counting Implementation

Application initialization

Sensor initialization

Application Workflows

1. Initialize the peripherals, the Bluetooth stack

2. Initialize and load the NVM3 configurations

3. Initialize the AK9753 sensor with the configuration loaded from NVM3:

   • Upper threshold: 100
   • Lower threshold: -200
   • IR Threshold: 800
   • Hysteresis: 50

4. Initialize OLED display

5. Start a periodic timer with a period of 1000ms, The timer callback will fire an external event to the BLE stack and the event handler will display people counting data from the result of the counting algorithm calculation.

6. After the sl_bt_evt_system_boot_id event arrives, application sets up the security manager to bond with an iOS/Android device. And then start advertising.

7. Handle GATT event to help users configure the counting algorithm and get the result from the algorithm calculation over the EFR32 connect mobile

Counting algorithm

The AK9753 sensor includes 4 IR sensors that are arranged in the picture below, and the detection algorithm will be based on the values of the IR2 and IR4.

We divide the ambient space into 3 areas: front, back and middle zone. Whenever a person appears in one of these 3 zones, a trigger will happen to notify that there is a person in this area and the status of this area will be also stored in a list. The order of these state values in the list is used to detect the moving direction of the person. For example, if the consecutive states in the list are 0, 1, 3, 2 or 0, 2, 3, 1 this means a person has been detected in one direction or the other.

When no-one is seen in either of the two zones, the list of states will be reset. The workflow of the whole algorithm is described in the picture below.

OLED Display

• Display the current people count and people entered so far values.

Button

• Press the button to reset the people count to 0.

Room status notification

• To receive the status of the room (full or empty), the user should use the EFR Connect Mobile Application to enable notification
• If the number of people counts is greater than the room capacity then the device will send a "room is full" notification
• If the number of people count is zero then the device will send a "room is empty".

Reset the counting value

• To reset the number of total people who entered the room, the user should use the EFR Connect Mobile Application to write 0 to the People Entered So Far characteristic
• To reset the number of people count, the user should use the EFR Connect Mobile Application to write 0 to the People Count characteristic.

Use EFR Connect Mobile Application

Connect to the device

The Silicon Labs EFR Connect application utilizes the Bluetooth adapter on your phone/tablet to scan, connect and interact with BLE devices. To run this example, an iOS or Android smartphone with the installed EFR Connect application is required.

Open the EFR Connect application on your smartphone and allow the permission request when opened for the first time. Click [Develop] -> [Browser] and you will see a list of nearby devices which are sending Bluetooth advertisements. Find the one named People Counting and click the connect button on the right side. If the application shows the pairing request dialog, press Pair button to confirm authentication for the pairing process. After that, wait for the connection to be established and the GATT database to be loaded.

Note: The pairing process on Android and iOS devices is different. For more information, refer to Bluetooth security.

Read/Write characteristics

The parameters of this example application can be easily configured via BLE characteristics. Values for the characteristics are handled by the application as ASCII strings. Tap on the main service to see the available characteristics. Please refer GATT Configurator to choose the correct characteristic.

Read:

Push the read button to request the value of a characteristic. (See ASCII fields.)

Write:

For setting a parameter select a characteristic and tap on its write button. Type a new value in the ASCII field and push the Send button.

People entered so far count	People count	Upper threshold	Lower threshold
- Read to get the current total people entered count - Write 00 00 to reset total people entered count	- Read to get the current people count - Write 00 00 to reset people count	- Read to get the current upper threshold setting - Write to set upper threshold settings	- Read to get the current lower threshold setting - Write to set lower threshold settings

IR threshold	Hysteresis	Notification status	Room capacity
- Read to get the current IR threshold setting - Write to set IR threshold setting	- Read to get the current hysteresis setting - Write to set hyteresis setting	- Read to get the current notification status setting - Write to set notification status setting	- Read to get the current room capacity setting. - Write to set room capacity setting